Effect of vitamin D supplementation versus placebo on recovery delay among COVID-19 Tunisian patients: a randomized-controlled clinical trial.

INTRODUCTION: The present study aimed to determine the impact of vitamin D supplementation (VDs) on recovery delay among COVID-19 patients. METHODS: We performed a randomized controlled clinical trial at the national COVID-19 containment center in Monastir (Tunisia), from May to August 2020. Simple randomization was done in a 1:1 allocation ratio. We included patients aged more than 18 years who had confirmed reverse transcription-polymerase chain reaction (RT-PCR) and who remained positive on the 14th day. The intervention group received VDs (200,000 IU/1 ml of cholecalciferol); the control group received a placebo treatment (physiological saline (1 ml)). We measured the recovery delay and the cycle threshold (Ct) values in RT-PCR for the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The log-rank test and hazard ratios (HR) were calculated. RESULTS: A total of 117 patients were enrolled. The mean age was 42.7 years (SD 14). Males represented 55.6%. The median duration of viral RNA conversion was 37 days (95% confidence interval (CI): 29-45.50) in the intervention group and 28 days (95% CI: 23-39) in the placebo group (p=0.010). HR was 1.58 (95% CI: 1.09-2.29, p=0.015). Ct values revealed a stable trend over time in both groups. CONCLUSION: VDs was not associated with a shortened recovery delay when given to patients for whom the RT-PCR remained positive on the 14th day. TRIAL REGISTRATION: This study was approved by the Human Subjects Protection Tunisia center (TN2020-NAT-INS-40) on April 28, 2020, and by ClinicalTrial.gov on May 12, 2021 with approval number ClinicalTrials.gov ID: NCT04883203 .

The Delta variant wave in Tunisia: Genetic diversity, spatio-temporal distribution and evidence of the spread of a divergent AY.122 sub-lineage.

Introduction: The Delta variant posed an increased risk to global public health and rapidly replaced the pre-existent variants worldwide. In this study, the genetic diversity and the spatio-temporal dynamics of 662 SARS-CoV2 genomes obtained during the Delta wave across Tunisia were investigated. Methods: Viral whole genome and partial S-segment sequencing was performed using Illumina and Sanger platforms, respectively and lineage assignemnt was assessed using Pangolin version 1.2.4 and scorpio version 3.4.X. Phylogenetic and phylogeographic analyses were achieved using IQ-Tree and Beast programs. Results: The age distribution of the infected cases showed a large peak between 25 to 50 years. Twelve Delta sub-lineages were detected nation-wide with AY.122 being the predominant variant representing 94.6% of sequences. AY.122 sequences were highly related and shared the amino-acid change ORF1a:A498V, the synonymous mutations 2746T>C, 3037C>T, 8986C>T, 11332A>G in ORF1a and 23683C>T in the S gene with respect to the Wuhan reference genome (NC_045512.2). Spatio-temporal analysis indicates that the larger cities of Nabeul, Tunis and Kairouan constituted epicenters for the AY.122 sub-lineage and subsequent dispersion to the rest of the country. Discussion: This study adds more knowledge about the Delta variant and sub-variants distribution worldwide by documenting genomic and epidemiological data from Tunisia, a North African region. Such results may be helpful to the understanding of future COVID-19 waves and variants.

Rapid diagnostic tests : Pros, cons and potential use in the COVID-19 management in Tunisia.

OBJECTIVES: Diagnosis of SARS-CoV-2 infection is a major public health issue. In a context of limited diagnostic capacity with the reference technique (real-time RT-PCR), many manufacturers have developed rapid diagnostic tests (RDTs). Although very promising in theory, these tests have raised many questions. This article is a rapid review that synthesizes data regarding different types of available RDTs, their performance, their limits and their potential indications in Tunisia as proposed by a multidisciplinary group of experts. METHODS: A literature review was carried out on the websites of international organizations, governmental bodies and on INAHTA database, completed by a search of relevant scientific articles up to 1 June 2020. The synthesis of the data was submitted to a panel of experts to propose recommendations for the Tunisian context. RESULTS: RDTs based on the detection of antigens and antibodies have sensitivity and specificity related issues. Few validation reports are published in the scientific literature. Pending more evidence on their performance and validity, several international organizations recommend their use only for research purposes. TDRs based on antibody detection are not appropriate for the early diagnosis of COVID-19. However, validated and specific tests could provide complementary diagnostic information to reference tests. CONCLUSION: Pending further evidence, the panel recommends the use of RDTs mainly for research purposes at the community level.

SARS-CoV-2 infection virological diagnosis.

SARS-CoV-2 infection has to be confirmed by virological diagnosis. Multiple diagnostic tests are available without enough perspective on their reliability. Therefore, it is important to choose the most suitable test according to its sensitivity and specificity but also to the stage of the disease. Currently, the RT-PCR detection of the viral genome in respiratory samples is the most reliable test to confirm the diagnosis of an acute SARS-CoV-2 infection. It has to be done in Class II biological safety laboratory. However, it may lack sensitivity, particularly in the advanced phase of infection, and depends closely on the samples' quality. Rapid PCR by cartridge system reduces response times but is not suitable for laboratories with high throughput of requests. Detection of virus antigens on respiratory samples is a quick and easy to use technique; however it has not good specificity and sensitivity and cannot be used for diagnosis and patient management. The detection of specific antibodies against SARS-CoV-2 is better used for epidemiological analyses. Research should be encouraged to overcome the limits of the currently available diagnostic tests.